1. Field of the Invention
This invention relates to drill insert parts, which provide the cutting edge or surface of a twist drill bit. More particularly, this invention relates to drill insert parts having a cemented tungsten carbide or similar hard material substrate, a polycrystalline diamond layer and one or more layers of a multi-metal material, which is generally inserted in the tip of a standard twist drill bit to provide enhanced wear resistance.
2. Description of Related Art
A variety of polycrystalline diamond drill inserts for use in drill bits, machining tools and the like have been proposed. Typically, these inserts have certain improved material properties and may include alternative metals and/or tungsten carbide and a few make use of a polycrystalline diamond surface layer. However, such prior inserts do not incorporate a multi-metal strip or layer bonded to the top surface of the diamond, which is fixed to a tungsten carbide substrate.
For general background, the reader is directed to the following U.S. Patents, each of which is incorporated by referenced in its entirety for the material contained therein.
U.S. Pat. No. 4,311,490 describes a process for preparing a composite compact, wherein a mass of abrasive crystals, a mass of metal carbide, and a bonding medium are subjected to a high-temperature/high pressure process for providing a composite compact.
U.S. Pat. No. 4,527,643 describes a cutting element, which consists of five cutting edges, which are comprised of polycrystalline diamond or the like mounted to a central carbide substrate of or similar hard material held by a rotatable shaft, which can be inserted into a drilling machine.
U.S. Pat. No. 4,627,503 describes a polycrystalline (diamond) material and metal element for use as a cutting element for drilling holes or similar uses. The cutting element comprises a polycrystalline diamond or CBN center portion and at least one metal side portion. The metal side portion is made from a soft metal having a Young""s Modulus less than approximately 45xc3x97106 psi and is selected from the group comprising cobalt, nickel, iron, copper, silver, gold, platinum, palladium and alloys of these metals and intermetallic compounds containing these metals.
U.S. Pat. No. 4,797,326 describes a process for fabricating a composite polycrystalline diamond or cubic boron nitride (CBN) compact.
U.S. Pat. No. 5,272,940 describes a rotary cutting tool that has a plurality of helical channels located in the body of the rotary cutting tool.
U.S. Pat. No. 5,304,342 describes a sintered product that is useful for abrasion- and impact-resistant tools and the like that comprises an iron-group metal binder and refractory metal carbide particles, e.g. tungsten carbide, formed in situ during sintering by the exothermic reaction of carbide-forming refractory metal powder with a carbon sourced mixed therewith.
U.S. Pat. No. 5,554,415 describes substrate coating techniques, including fabricating materials on a surface of a substrate where energy, such as from one or more lasers, is directed at the surface of a substrate to mobilize and vaporize a constituent element within the substrate.
U.S. Pat. No. 5,620,754 describes a method of treating and coating substrates that uses energy, such as from one or more lasers, directed at the surface of a substrate to mobilize and vaporize a constituent element within the substrate.
U.S. Pat. No. 5,643,641 describes a method of forming a diamond coating on a polymeric substrate that uses energy, such as from one or more lasers, directed at the surface of a substrate to mobilize and vaporize a constituent element within the substrate.
U.S. Pat. No. 5,648,127 describes a method of applying, sculpting, and texturing a coating on a substrate and for forming a heteroepitaxial coating on a surface of a substrate that uses energy, such as from one or more lasers, directed at the surface of a substrate to mobilize and vaporize a constituent element within the substrate.
U.S. Pat. No. 5,650,059 describes a method of making a cemented carbide substrate that includes preparing a binder to receive a cutting material such as a diamond coating.
U.S. Pat. No. 5,679,159 describes a mandrel for use in an arc-jet spinning diamond deposition process for coating cutting tool inserts.
U.S. Pat. No. 5,681,653 describes diamond-cutting tools, where single hard particles or single point cutting tools having the particles bonded thereto are coated with a modulated or layered composition of transition metal compounds or with titanium compounds to decrease mechanical failure of the particles.
U.S. Pat. No. 5,709,907 describes a method of producing a cutting tool that comprises a substrate, which has a roughened surface that presents a surface roughness of between 15 microinches and 125 microinches. A coating is applied to the roughed surface of the substrate by physical vapor deposition.
U.S. Pat. No. 5,722,803 describes a coated cutting tool and a method of producing the same, that comprises a substrate with a roughened surface and a coating applied to the roughened surface by physical vapor deposition.
U.S. Pat. No. 5,731,046 describes the fabrication of diamond and diamond-like carbon coatings that uses energy, such as from three different lasers, directed at the surface of a substrate to mobilize and vaporize a carbon constituent element within the substrate.
U.S. Pat. No. 5,731,079 describes diamond cutting tools having single hard particles or single point cutting tools having the particles bonded thereto are coated with a modulated or layered composition of transition metal compounds or with titanium compounds.
U.S. Pat. No. 5,934,842 describes a high-speed milling cutter that includes a hub rotatable about an axis, a plurality of radially extending arms, and a plurality of cutting inserts, each of which is connected to a distal portion of one of the arms.
U.S. Pat. No. 5,952,102 describes a diamond-coated tungsten carbide composite, which uses diamond layer coated on the substrate by a chemical vapor deposition process.
It is desirable to provide a polycrystalline diamond drill insert component with lower tensile stresses and hence a lower propensity for delamination.
Therefore, it is the general object of this invention to provide a drill insert component made by sandwiching polycrystalline diamond (PCD) between a layer, preferably but not exclusively of cemented tungsten carbide, or similar hard material, and a multi-metal layer for improved interlayer bonding and a lower propensity for delamination.
Another object of this invention is to provide a drill insert component where the multi-metal layer is made of an inner layer of preferably but not exclusively niobium and an exterior layer of preferably but not exclusively molybdenum. In alternative embodiments of this invention, the multi-metal layers are selected from tantalum, zirconium, tungsten, cobalt, nickel, iron, copper, silver, gold, platinum, palladium, molybdenum, niobium, and other similar refractory metals, as well as alloys of these metals and/or intermetallic compounds containing these metals, and may be used in the form of foils, tapes, powders, and/or CVD or PVD coated metal layers.
It is a further object of this invention to provide a drill insert component using a multi-metal layer, which has an intervening layer to reduce stresses in the insert.
A further object of this invention is to provide a diamond drill insert component with an improved bond between a metal layer and the polycrystalline diamond layer.
It is another object of this invention to provide a drill insert component that reduces or eliminates detrimental, complex carbide reactions typically found in the use of certain metals.
It is a still further object of this invention to provide a drill insert component that uses a combination of materials, which create an alloying effect, thereby enabling the selection of different materials properties using the modulus of the chemistry of the metals and the thickness of the layers.
Another object of this invention to provide a drill insert component that makes use of the processing can in the composition of the drill insert component.